Steady State Axisymmetric Penetration of a Kinematically Hardening Thermoviscoplastic Target

We study axisymmetric thermomechanical deformations of a thick target being penetrated by a fast-moving rigid cylindrical rod with a hemispherical nose, and presume that target deformations appear steady to an observer situated at the penetrator nose tip. Both isotropic and kinematic hardening of the target material are considered. It is found that kinematic hardening increases the normal stress acting on the penetrator nose surface and the temperature rise of target particles abutting the penetrator. However, the value of the hydrostatic pressure at a point in the deforming target region is affected very little by the consideration of kinematic hardening. For suitable values of material parameters appearing in the evolution equation of the back-stress, the computed values of the back-stress at target particles abutting the penetrator nose surface equal three times the yield stress of the target material in a quasistatic simple compression test.